The present invention relates to quality of service control in networks, and more specifically, to providing a certain level of quality of service in a network which includes both wireless and wire line infrastructure through reservation of resources.
Conventionally, the Internet has not provided mechanisms for differentiation of the quality of service of various traffic routed over the Internet. Accordingly, all packets which traverse the Internet are treated equally when being forwarded by routers in the Internet. However, recently there has been a demand for quality of service differentiation in packets traversing the Internet. This demand for quality of service differentiation is due in part to applications being used across the Internet with various demands for high throughput and low delay. Further, users of the Internet have shown an increased willingness to pay for improved quality of service for traffic on the Internet.
To address the demand for differentiation of quality of service in the Internet, the Internet Engineering Task Force (IETF) has proposed one mechanism which is known as Integrated Services Architecture and which uses RSVP. The mechanism is based on soft end-to-end signaling to provide sensitive applications with admission control and per flow quality of service in routers along data paths. However, this approach has been dismissed as too complex due to the fact that the original design of the Internet is stateless in that the routers do not need any information about application data flows in order to route the data. Adding per flow connection state in routers changes this model of the Internet router so that it does not scale as well into the original design of the Internet.
Another approach to providing differentiated services over the Internet by the IETF is known as the diffserv architecture. In the diffserv architecture, IP packet headers include a small label, known as the diffserv field, to identify the forwarding treatment that particular packet should be provided by routers. Core routers are configured with a few per-hop behaviors which are matched to the packet labels so that these routers can forward packets in accordance with a priority of their forwarding class. The diffserv architecture relies on the use of traffic conditioners, including packet markers, traffic shapers and policing functions, at the boundaries of the network to ensure that the traffic load is controlled and that intended services are provided in the various forwarding classes.
One known method for controlling a minimum quality of service in a network is through admission control. Admission control allows a network operator to reject service to new clients so that committed service can be provided to clients that were already granted admission. One method for admission control in the diffserv architecture is through the use of boundary routers and policy servers. FIG. 1 illustrates a conventional policy server architecture for admission control to a network. The architecture illustrated in FIG. 1 includes a client 110, access router 120, including a policy enforcement point 125, a policy server 130, including a policy decision point 135, and a network 140. To gain access to network 140, client 110 sends its request for access to access router 120. Policy enforcement point 125 in access router 120 forwards the request for admission to policy server 130. The policy decision point 135 in policy server 130 determines whether to allow client 110 access to network 140. Policy server 130 returns this decision to access router 120, which in turn, either allows or denies client 110 access to network 140. The decision of whether to allow or deny access to network 140 by policy server 130 is not based upon the available resources of network 140, but instead is based upon policy decisions such as whether client 110 has a right to reserve access in network 140, e.g., whether client 110 is a paying customer of network 140.
FIG. 2 illustrates another conventional admission control architecture. The admission control architecture illustrated in FIG. 2 includes client 210, access router 250, including traffic classifier/traffic shaper 255, bandwidth broker (BB) 260 and network 240. To gain admission to network 240, client 210 sends a request to access router 250. Access router 250 forwards the request for bandwidth to bandwidth broker 260. Bandwidth broker 260 determines whether there is enough bandwidth in network 240 to grant the request of client 210. Bandwidth broker 260 forwards this decision to access router 250, which then allows or denies client 210 the reserved access to network 240. If client 210 is granted access to network 240, traffic from client 210 is shaped by the traffic classifier/traffic shaper 255 located in access router 250.
It will be recognized that there are two general types of bandwidth reservation which a bandwidth broker typically deals with, open ended immediate reservation and in advance reservations. An open ended immediate reservation is a reservation that is made for the present time and does not have a deterministic end time. This type of reservation is provided only with a limited guarantee for bandwidth in a network. The services with immediate reservation have lower priority than the services with in advance reservation in the sense that a service with immediate reservation may be preempted in case resources have to be reallocated to a service with in advance reserved resources. This risk of preemption is viewed as an acceptable tradeoff against the target of maximum utilization for reserved resources. Accordingly, this risk of preemption is configured to an acceptable level.
An in advance reservation is a reservation for a future point in time which is guaranteed for the duration of the reservation. By offering in advance reservations, clients can more effectively plan their network activities. In advance reservations are typically used for scheduled events and when long term aggregate resources are negotiated between different providers.
To provide committed service in their domains, bandwidth brokers set up traffic conditioners in boundary routers of their diffserv domains. Traffic conditioners perform packet marketing, policing and traffic shaping. Thus, traffic conditioners are used to ensure that the clients maintain their bandwidth within the amount that they reserved and that the intended services are provided in the various forwarding classes. Traffic in excess of a reservation is either dropped or remarked to a lower service level.
As the Internet continues to evolve, it is anticipated that wireless access to the Internet will continue to increase. It is envisioned that Internet protocol (IP) will one day be used end-to-end, including over wireless links, so that mobile units can be provided with the opportunity to support a vast range of applications in traffic mixes.
In the current wired Internet, and in IP-based wireless local area networks (WLANs) congestion in the network can result in increased delays to packets traversing the network and to dropped packets. However, since the bandwidth of these networks is quite large, and the transmission speed of data through these networks is also quite quick, these network delays and dropped packets are not viewed as a great problem. However, in wide area wireless networks, i.e., networks which operate in government license bands where end users typically pay a traffic fee per minute for use of the network, e.g., WCDMA or GSM, bandwidth is quite expensive. Accordingly, it would be a waste of this precious bandwidth if packets which have entered the network over a wireless link are dropped in the wired backbone. Accordingly, it would be desirable to provide a sufficient amount of resources in the backbone network for carrying the expensive wireless traffic.
Although there are known mechanisms in network elements to enforce resource provisioning such that per packet service differentiation is provided, there is currently a lack of resource management mechanisms for anticipating the amount of traffic that needs to be provided with better service and for provisioning the network resources for this. Resource management mechanisms for wireless service needs to anticipate a greater number of factors than resource management mechanisms for wireline service. These factors include the geographic location from which access will occur, the type of access technology to be used for the access and the mobility during the particular wireless access.
FIG. 3 illustrates the geographical location problem of wireless reservation access. Assume that a client at time and space location A wishes to make a service reservation, i.e., to reserve network resources. Since the client has wireless access, the client may be mobile, and may be reserving access at time and space point A for a different location in the future time at time and space point B. Accordingly, it would be desirable to provide mechanisms in wireless reservation to account for reservations systems which are made in a particular geographic location for a connection at another geographical location.
Access technology can be divided into two major categories based primarily upon the area of coverage provided by the access technology, local area wireless networks and wide area wireless networks. Access technologies which can be classified as local area wireless networks include Bluetooth and wireless local access networks (WLAN). Bluetooth networks operate in the 2.4 GHz frequency band and are intended to remove the requirement of cables between various devices. Bluetooth networks typically have nominal range of 10 cm to 10 m and a gross data rate of 1 Mpbs. WLAN networks can operate in the 2.4 GHz frequency band and can be used to provide laptop computer users with mobility without compromising the performance or security provided by wired LANs. It is anticipated that the 5.2 GHz band will be opened to be dedicated to WLAN like applications. WLANs operating in the 2.4 GHz frequency band have a nominal operating range around 400–500 m and a gross data rage of approximately 3 Mbps. WLANs operating in the 5.2 GHz range have a nominal operating range of 30–200 m and a gross data rage of approximately 20 Mbps. It should be noted that the 2.4 GHz frequency band used by both Bluetooth and WLANs is an unlicensed frequency band, i.e., devices operating in this frequency band do not require licenses from government entities. Accordingly, the amount of time spent communicating in this frequency band is comparatively cheaper than the same amount of time spent communicating over a frequency band which requires licenses.
Access technologies which can be classified as wide area wireless networks include conventional networks referred to generally as cellular networks, e.g., Global System for Mobile Communication (GSM) networks, General Packet Radio Services (GPRS)/Enhanced Data for GSM Evolution (EDGE) networks and Universal Mobile Telecommunication Systems (UMTS) networks. The access technologies generally provide services up to 20 km from a base station and operate over licensed frequency bands. The gross bit rate provided in GSM networks is a maximum of 14.4 kbps, the gross bit rate in a GPRS network can vary between 10–120 kbps and a GPRS with the EDGE extension can provide up to 384 kbps. In a UMTS network there is a maximum bit rate of 2 Mbps, but most of the time the maximum bit rate will be around 384 kbps for wide area coverage.
The mobility of a user refers to the amount of movement of a particular user. A high mobility user, i.e., a user with a large amount of movement, cannot use a local area wireless network, but instead must select a wide area wireless network. In addition, a high mobility user which communicates in a wide area wireless network may move between cells supported by different base stations. Switching between these different base stations is known as handover. Accordingly, a reservation scheme for wireless users should account for the possibility that a user may handover between various portions of the wireless network.
Accordingly, it would be desirable to provide a reservation system for wireless networks for transporting information over wired networks.
It would also be desirable to provide a reservation system which is scalable within the Internet architecture.
Further, it would be desirable to provide a reservation system which allows for both immediate reservations and in advance reservations.
It would also be desirable to provide a reservation system which accounts for the actual geographic area for which the reserved communication is to take place. In addition, it would be desirable to provide a reservation system which accounts for the advantages and limitations of various access technologies. It would also be desirable to provide a reservation system which accounts for the mobility of a user.